1. Field of the Invention
The present invention relates to a post coupler, and particularly to a flush mount breakaway post coupler for coupling parking meter posts, sign posts, fence posts and the like to an anchor mounted in the ground so that when the post is subjected to an impact above a threshold limit, the post coupler breaks flush with the ground leaving only a narrow annular hole exposed.
2. Description of the Related Art
Many cities an towns install parking meters and signs on posts mounted in sidewalks, concrete median strips and the like. The posts supporting the meters or signs will typically have a ground anchor driven below the depth of the concrete, and the post will telescope into or onto the anchor. When such posts are impacted by an errant motorist, snow plow, or other moving vehicle, the vehicle will be damaged if the post is fixed to the anchor. In addition, the post and/or anchor are frequently damaged, as well as the concrete surrounding the ground anchor. Even when some form of breakaway coupling is used, so that the post breaks away from the anchor on impact, there will typically be either a length of ground post or coupler left exposed above ground, or there will be a hole left in the sidewalk which can pose a hazard to pedestrians. A hole left in a sidewalk is often a magnet for women who wear high heels, for the elderly and infirm, for small children, and for the inattentive pedestrian. Damage to such posts can result in expensive repairs to or replacement of the post, expensive repairs to the surrounding pavement, exposure to potential lawsuits for property damage and personal injuries resulting from hazardous conditions resulting from a damaged post until repair and replacement, and other adverse economic and social costs.
A further problem with existing breakaway post couplers is that many existing couplers are not designed to shear with equal facility depending upon the angle of incidence of the impact. Many couplers only break cleanly when a sign or meter is struck head on, and require considerably more force to shear when struck obliquely, if they shear at all under such conditions.
It is therefore desirable to have a post coupler which mounts so that the shear point is flush with the ground, leaving no portion of the post projecting above ground after fracture, and which shears without leaving an unfilled hole upon fracture. It would further be desirable to have such a post coupler which is easy to install, and which will leave the ground anchor and surrounding pavement undamaged on fracture. Several patents have been directed to breakaway post couplers, but none display all of the structure and resulting advantages featured by the present invention.
U.S. Pat. No. 3,628,296, issued Dec. 21, 1971 to H. J. Henry, shows a breakaway sign post with three sections, one a ground anchor, the second a reinforcing section telescoping around the ground anchor, and the third a post which telescopes into the ground anchor. All three sections are tubular, polygonal, and perforated so that the post breaks due to the weakened cross section caused by the perforations. This post suffers from the disadvantage of not being able to break cleanly at all impact angles due to the polygonal shape, as well as breaking at multiple points due to the perforated structure. U.S. Pat. No. 5,535,555, issued Jul. 16, 1996 to Boyd et al., shows another coupling device which uses holes or apertures to define a shear point.
U.S. Pat. No. 4,850,565, issued Jul. 25, 1989 to A. M. Moreno, shows a ground post with a U-shaped channel at the top of the post with a first cylindrical member welded inside the channel, a U-shaped channel having a second cylindrical member welded to the inside of the channel, and a shear pin extending through aligned bores in the first and second cylindrical members. U.S. Pat. No. 5,004,366, issued Apr. 2, 1991 to G. H. Simmons, and U.S. Pat. No. 5,855,443, issued Jan. 5, 1999 to Faller et al., also show couplers which utilize shear bolts.
U.S. Pat. No. 4,638,608, issued Jan. 27, 1987 to W. H. Coy, U.S. Pat. No. 4,926,592, issued May 22, 1990 to C. O. Nehls, U.S. Pat. No. 5,782,040, issued Jul. 21, 1998 to D. McCartan, and U.S. Pat. Nos. 3,820,906 and 3,846,030, both issued to H. L. Katt on Jun. 28, 1974 and Nov. 5, 1974, respectively, all show breakaway couplers in which the shear point is mounted above ground.
U.S. Pat. No. 5,214,886, issued Jun. 1, 1993 to D. P. Hugron shows a breakaway coupler in which the sign post and ground post are not completely severed. U.S. Pat. No. 5,425,593, issued Jun. 20, 1995 to R. J. Buehler, shows a sleeve with upper and lower receptacles with receive the sign post and ground post, respectively. U.S. Pat. No. 5,480,121, issued Jan. 2, 1996 to Rice, et al., describes a breakaway connector having two U-shaped sections bolted to the sign post and the ground post, the U-shaped sections being joined by a hollow stud welded to the web of each connector. The hollow stud has an annular groove about its center and two aligned bores extending transversely through the groove.
My own prior U.S. patent application, Ser. No. 09/238,057 filed Jan. 27, 1999, now issued as U.S. Pat. No. 6,113,055 on Sep. 5, 2000, shows a sign post coupler with a sign post socket and a shear section identical to those of the present invention. The present invention differs from the sign post coupler described in my prior application in that the coupler of the prior application has a ground post socket for receiving a ground post, whereas the present invention uses a wedge to secure the coupler to a ground anchor which is embedded in concrete, and the shear section is at least partially filled after rupture by a bolt head.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Thus a flush mount breakaway post coupler solving the aforementioned problems is desired.
The flush mount breakaway post coupler is a coupler for connecting a post to a ground anchor. The coupler has an upper section and a lower section. The upper section has a socket for receiving a post, a shear section, and an anchor attachment portion for attachment to the lower section. The shear section is hollow and cylindrical and has an groove defined about its exterior so that the wall of the shear section is thin, fracture of the coupler occurring around the annular groove. The lower section is an expansion anchor having a threaded bore for receiving a bolt, the lower section being placed in a tubular ground anchor, or a hole defined in the ground. The socket has a bottom wall, and a cylindrical bore extends through the shear section to a predetermined base in the anchor attachment portion. A bolt hole extends from the base of the bore through the anchor attachment section. A bolt connects the upper and lower sections so that the coupler is wedged into the tubular ground anchor as the bolt is tightened. The coupler is installed with the shear section coplanar with ground level. When the coupler fractures, the socket breaks off, leaving no portion of the coupler above ground, and the remaining annular edge of the shear section and the top surface of the bolt head level with the surface of the ground.
Accordingly, it is a principal object of the invention to provide a flush mount breakaway post coupler for supporting a parking meter, sign post, fence post, and the like with a shear section installed at ground level so that the coupler breaks at the shear section when the post is impacted by a force, such as a motor vehicle collision with the post, leaving substantially no portion of the ground anchor or post exposed above ground.
It is another object of the invention to provide a breakaway post coupler which leaves a portion of the coupler substantially coplanar with the surface of the ground after shearing so that an unfilled hole is not left exposed after the post has broken away.
It is a further object of the invention to reduce the economic costs to municipalities of repairing and/or replacing posts and the pavement surrounding post installations resulting from damage to is sign posts and parking meters.
Still another object of the invention is to reduce the risk of personal injuries and damage claims resulting from damaged post installations in municipal areas by providing a breakaway post coupler with shear section flush mounted at ground level and which remains at least partially filled after the post is broken away.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.